Police in Henrico, Va., were waiting at school for the little boy Monday morning after he allegedly threatened another pupil on their ride to Ratcliffe Elementary School. They found a handgun in his backpack, NBC station WWBT of Richmond, Va. reported.

The incident made national headlines Monday, as did a similar incident when a loaded gun was found in a pupil's book bag last month at P.S. 215 in Queens, N.Y.

However, these incidents aren't as isolated as they may appear. An NBC News survey of crime dockets and news reports across all 50 states reveals that, since Jan. 1, there have been at least 48 incidents in which guns have been discovered on students, in their bags or in their lockers.

There have been 23 class days since some districts resumed school Jan. 2 — not including Jan. 21, the Martin Luther King Jr. holiday. That works out to more than two gun reports a day this school year. (The survey excluded incidents in which pupils were caught with toy guns; all of the weapons were handguns, rifles, BB guns or air rifles.)

And those are just the cases that have been made public: Juveniles' police records are generally protected, so an untold number of other such incidents are likely to have occurred.

While it's impossible to determine whether such potentially deadly show-and-tells are happening more frequently, the public data do indicate just how hard it is to clamp down on guns on campus since the issue became a national concern in December in the wake of the fatal shootings of 20 pupils at Sandy Hook Elementary School in Newtown, Conn.

Most of the time, the weapons are brought along for protection or as items of curiosity, with the pupil more interested in showing off than in shooting. And usually, they're intercepted before anyone can get hurt, with the student's being suspended or charged for a weapons violation, depending on his or her age. Often, a parent or guardian is charged with failing to secure the weapon.

"Gun violence in and around our schools is simply unconscionable and must end," Atlanta Mayor Kasim Reed said. "Too many young people are being harmed and too many families are suffering from unimaginable and unnecessary grief."

While many lawmakers have introduced legislation that would put armed police or security guards in schools, that may not be the answer, according to a state task force reviewing campus safety in Virginia.

The task force last week stressed the need to fund anti-bullying programs and school resource officers, but it stopped short of calling for more officers in schools.

"If we were to put 1,000 new police officers in our schools, those police officers would have to come from somewhere, and we might inadvertently make things less safe in our communities," Dewey G. Cornell, a law professor at the University of Virginia who's a member of the task force, told WWBT.

The boy who opened fire last week in California was one of those who carried a weapon because he said he had been bullied, Kern County Sheriff Donny Youngblood said.

But that's not a good enough excuse, parents say.

"That just doesn't make sense," said Jeremy Massey, the parent of a student at Daly Elementary School in Inskter, Mich., near Detroit, where a third-grader was found to have taken a loaded gun to class two days in a row last month. The boy told police he carried the gun for his own protection.